This specifies a table column from which data values are to be retrieved by the query.

The

function

argument can be an

aggregate

,

cast

,

string

,

math

, or

date

function. The function is applied to a value expression argument, producing a derived column as its result. Consult the Functions section for a description of the available functions.

A numeric or string constant can also be specified in the select list. The effect on the output table is a derived column where the constant is the value for each row in that column. This might be useful, for example, in labeling the output. String literals must be contained between single quotes.

A complete SELECT statement that returns a single value. If more than one row is returned by this subquery, an error will be generated and the outer query will fail. If the subquery result set is empty, a null value is returned. The entire scalar subquery must be contained in parentheses.

Note that a

correlated

subquery is not permitted at this time.

The + (addition), - (subtraction), * (multiplication), and / (division) operators are used to construct arithmetic expressions. The || (concatenation) operator is used to append one string value expression to the end of another. An exception is that aggregate functions cannot be part of an arithmetic expression.